Sorption and diffusion of acrylonitrile monomer through crosslinked nitrile rubber

As the first step for the preparation of interpenetrating polymer networks from nitrile rubber and polyacrylonitrile, the sorption and diffusion of ac rylonitrile monomer through nitrile rubber crosslinked by three different v ulcanization systems - conventional (CV), dicumyl peroxide (DCP), and a mix ture consisting of sulfur and peroxide (mixed) - were studied in the temper ature interval of 30-70 degrees C. Kinetic curves have been generated for t hese systems to compute diffusion and sorption coefficients. The equilibriu m sorption is found to be maximum for the CV system. The molar mass between crosslinks (M-c) has estimated and compared with affine and phantom models . It was found that the M-c values follow the affine model. The diffusion c oefficient values are highest for DCP and lowest for CV. It was observed th at the kinetics of liquid sorption followed an anomalous behavior. The temp erature dependence of the transport parameters was followed by an Arrhenius relationship, from which the activation energy for diffusion, permeation, and sorption were calculated. It is found that temperature activates diffus ion in all cases. The polymer-solvent interaction parameter was determined. The amount of polysulfidic linkages in the rubber network was also estimat ed. The experimental results were compared with theoretical predictions. (C ) 2000 John Wiley & Sons, Inc.